Apparatus for treating rubber articles.



J. T. CROWLEY.

APPARATUS FOR TREATING RUBBER ARTICLES.

APPLICATION FILED NOV. I0, I916.

1,2253%, Patented May15,1917.

Y .T A 5' 3 wvemioz at? GE JOHN T. CROWLEY, OF BEACON FALLS, CONNECTICUT, ASSIGNOR TO THE BEACON FALLS RUBBER SHOE COMPANY, OF BEACON FALLS, CONNECTICUT, A CORPORATION OF CONNECTICUT.

APPARATUS FOR TREATING RUBBER ARTICLES.

Specification of Letters Patent.

Patented May 15, 1917..

Application filed November 10, 1916. Serial No. 130,527.

sidingilin Beacon Falls, in the county of New aven and State of Connecticut, have invented certain new and useful Improvements in Apparatus for Treating Rubber Articles, of which the following is a specification.

This invention relates to the vulcanization of hollow rubber articles, and has for an object to provide suitable apparatus whereby the article under treatment is caused to closely hug the form on which it is cured, the various plies of the article, if this is of a built up structure, are closely drawn together and united, and, if the article is ormed with a fabric lining-such as an article of footwear, the outer portion is closely drawn into union with the lining and the entire article caused to conform to the last, and whereby the mass of the article is freed from occluded gases and volatile substances and closely compacted, and all gases and vapor generated within and upon the form are removed.

This invention, although capable ofgeneral application, is peculiarly adapted to the vulcanization of rubber footwear on wooden lasts in dry heat. 7

Heretofore it has been proposed'to vulcanize hollow rubber articles by mounting them on suitable forms and sealing the free edge of the article to the form and subjecting the respective sides of the article to differential pressures during vulcanization. In these differential pressure processes it has always been necessary to furnish a seal or dam whereby the higher pressure on the outer side will not be communicated to the inner or form side of the article in communication with the lower pressure. According to this present invention such sealing is not necessary, although the inner side of the article is communicated with the lower pressure.

In using my invention the hollow article to be vulcanized is placed upon or built around, as the case may be, the pervious form, and differential pressures are applied to the respective sides of the article during at least the early portions of the heat treatment, the interior of the form being connectfootwear.

ed with a lower pressure than that upon the outer side of the article.

It 1s also part of my invention in the manufacture of footwear, for instance, rubber overshoes having a fabric lining, to provide a chamber within the, pervious last extending toward those portions of the last where there are cavities or depressions, as for instance, at the juncture of the heel with the sole, so that the diiferential pressure causes the shoe to closely hug the last and draw all the plies of rubber andfabric together. This invention does away with a great deal of the hand work now individually bestowed upon each article of rubber It also permits of a cheap and rapid manufacture or building up of the article, in that it can be built up upon the ordinary wooden last without recourse'to seals and dams at the top edge.

In the use of wooden lasts great difficulty is experienced in dry heat processes, particularly in the open oven process, from the moisture which gets in or upon the lasts during certain climatic conditions. When these climatic conditions exist, particularly in certain seasons of the year, moisture either in fluid form or as a gas, is generated from the lasts and has a tendency to injure the article being treated, and also prevents it closely adhering to the surface of the last.

' This objectionable feature is completely done away with in my present improvement.

Reference is made to the accompanying drawings, showing an example of the apparatus which I have found useful in practice, wherein,

Figure 1 is a sectional view showing an illustrative example of a pervious form having upon it a rubber article, and

Fig. 2 is a longitudinal sectional view of a pervious last having mounted thereon a rubber shoe.

In carrying out my invention a form for the hollow article to be vulcanized is provided. This form is made of some suitable porous material, as, for instance, plaster molded in some suitable form, an example of which is illustrated at 5 in Fig. 1, or pervious wood is used, an example of which is illustrated at 6 in Fig. 2. The article is.

either formed and placed upon the form or last or is built up on it. When the improved form. is used in connection with rubber footwear, the article is built up upon the last in the usual manner. After the article is properly placed upon or built around the form, the article and form are placed in a suitable vulcanizing chamber andsubjected to a suitable vulcanizing medium, preferably dry gas, and the interior of the pervious form is placed in communiout its entire contour.

The porous form employed by me,

' I whether a wooden last or some other porous material, presents upon'its surface a myriad of months which communicate the lower pressure to the entire inner surface of the hollow article undergoing treatment.

For the better-application of the lower fluid pressure to the interior of the article, this is preferably cored out thereby pro-- yiding a chamber adapted to be placed in communication with a source of lower pressure than that existing within the .vulcan izing-chamber and applied to the exterior of the article. Thislow pressure chamber preferably passes in the region of, or approaches the deeper depressions or cavities of the mold surface. In Fig. 1, at the plane on which the cross-section of the form 5 is taken, there is at the portion farthest from the base an enlargement, and between such portion and the base there is a contracted or neck-like portion 7. The rubber article in this figure is designated by the reference character 8, and will be assumed to be formed in any desired or well known manner of makin hollow rubber articles. The chamber 9 wlthin the form, illustrated in this figure,'.e'xtends into the enlarged por-. tion and is so located relatively to the neck portion 7 that the overlying rubber article upon the outer surface qf a table 10, such receives the full benefit of lower fluid pressure within such chamber 9 than that .pre sented by the vulcanizing medium to the exterior of the article. One feature of my invention is to dispose the low pressure or suction chamber adjacent those portions of the form away from which the rubber article is inclined to move, andalso adjacent the cavities of the form into which it is diflicult to force the rubber in the building up operation: v V

The form 7 in Fig. 1' is shown resting table being shown provided with a chamber 11 having an opening 12 registering with the chamber 9 when the form is in proper position upon the table. A conduit 13 is shown leading from the chamber 11, such conduit being'assumed to be connected to some suitablesource of low pressure, as, for instance, a vacuum pump. For certain classes-of work a plaster or cement form is quite desirable. In other classes of Work, however, such as, for instance, the commercial manufacture of rubber footwear, wooden lasts are more desirable,.particularly when the vulcanizing medium is dry heat. Such a last is shown in Fig. 2, represented by the reference character 6. vThis last is assumed to be the ordinary wooden last,

preferably made of maple wood A rubber overshoe illustrated in a conventional manner is shown mounted upon this last. Although the rubber shoes may, and generally will be,-built up according to the usual practice of rubber shoebuilding, yet for simplicity in the present illustration it is shown i with an outer layer of rubber 14 upon a fabric lining 15,.which lining is interposed between the layer of fabric and the last or orm.-

The most convenient manner of applying the lower pressure to the interior of the commercial wooden last is to bore a hole 16 in the top of the last and permit this hole, which constitutes a chamber, 7 to extend a suitable distance beyond the top edge of'the rubber overshoe. To prevent leakage from the chamber 16 through that portion of the last which is not covered with the rubber article, an impervious sleeve 21 may be inserted into the-bore 16 and extend upwardly a slight distance beyond the upper edge of the overshoe. The outer-end of the bore 16 is shown flaring to better receive and hold the tapering sleeve illustrated. This sleeve may also constitute a portion of a connection with a suitable source of low pressure, as, for: instance, it may be slightly flaring in-v teriorly and adapted to fit a tapered nipple 22- carried by a conduit 23 extending to the atmosphere or to a suction pump. The sleeve 21 is shown provided with a flange 24.

for supporting a plurality of the articles in [The flange is illustrated as having a notch L the vulcanizing chamber in a well known manner;

It is to. be noted that the 'upper portion of the overshoe indicated by the reference character 27 need not be sealed to the form or last,-nor need the exposed portions of the last be insulated.

The low pressure chamber preferably extends an appreciable distance within the last and may extend well into the heel and adjac'ent the portion 17 which represents the angle between the front of the heel and the instep portion of the sole. This extension of the chamber is represented by the reference character 16'. In certain cases it is also desirable to extend thelow pressure chamber throughout practically the entire length of the last. This can conveniently be effected by a transverse bore, as 18, projecting from the heel toward the toe of the last, and also passing adjacent the region of the depression 19 between the toe and the instep portions. This transverse bore 18 may enter the back of the last andbe closed by a suitable, but preferably pervious, plug 20.

As an illustrative example of the operation of my invention, the manufacture of a rubber shoe is herein described. Of course, it is to be understood that the invention is not limited either to rubber shoes or other articles of footwear, but is applicable to various hollow rubber articles. For making the wooden form for use in the treatment of rubber overshoes, which form in the illustrative example is a last 6, some suitable permeable wood is selected. In fact, most of the woods now employed for lasts for the manufacture of rubber footwear are suitable for this purpose. Maple is quite generally employed for lasts used in the large rubber factories. Hardness or density of the wood, so long as it is sufliciently permeable for the carrying out of the process, is a desirable feature. The last is given the desired form exteriorly to produce the proper shape offinished overshoe, and this last is provided with means for communicating its interior with a fluid pressure lower than that which is to be exerted upon the outer side of the shoe by the vulcanizing medium. The form and details of a practicable arrangement of interior spaces are set forth in the above description with particularity. The rubber shoe is built up in any desired manner upon the last, preferably with a fabric lining in communication with the surface of the last.

Attention was above called to the fact that 'it is not necessary to seal the edge 27 of the article to the form.

In building up the overshoe the workman need not be particular to secure an intimate connection between the various plies of fabric, norto force the built up article completely into the cavities'and depressions of the last. After the overshoe has been built up the last is connected with the source of lower pressure, in the present illustration by being mounted upon the nipple 22 carried by the pipe 23. This pipe may, if desired, carry a large number of shoes, and with them be placed into the vulcanizer. If the vulcanizing medium is heated air at about atmospheric pressure in the open heat chamber, it will be suflioient to connect the interior of'the last with the atmosphere, either during the earlier stages of the application of the vulcanizing medium, or, if desirable, through the entire period. Owing to the fact that the preferable material for making the forms is wood, the vulcanizing medium should be a dry gas. After vulcanization it is found that the overshoe isfree from blisters and open spaces, and that the rubber stock is compacted, particularly at the heel, and that the entire thickness of the article has been drawn closely down into the depressions of the last.

What I claim is:-

1. A porous wooden last having a cham-' ber within the foot portion and means for communicating the said chamber with a source of low fluid pressure.

2. Asolid last of porous material having a chamber within it, the walls being thinnest near the concave portions of the exterior where the greatest suction effect is required, and means for communicating such chamber with a source of low fluid pressure.

3; A last for rubber footwear of porous material having a chamber with portions approaching the juncture between the heel portion and the sole portion, and the incurve between the instep portion and the toe portion, and means for connecting the said chamber with a source of low pressure.

4;. A form comprising a wooden last having a bore extending from its upper portion toward the heel and a bore extending longitudinally of the last, and means for connecting said bores with a desired condition of fluid pressure.

5. A form comprising a wooden last having a bore extending from its upper portiontoward the heel and adjacent the juncture I between the heel portion and the sole portion, and a bore extending longitudinally of the last and adjacent the in-curve between the instep portion and the toe portion, and means for connecting said bores with a desired condition of fluid pressure.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses. JOHN T. CROWLEY. Witnesses:

LEM C. WARNER,

CHAS. LYON RUssnLL. 

